Electric discharge tube



May 17, 1932.

J. H. J. MAARTENS ELECTRIC DISCHARGE TUBE Filed No 22, 1929 INVENTOR J. H.J. MAARTENS 7 k 7 ATTORN Y Patented May 17, 1932 ETEEE STATES ro-nannns nnnnnrcns aosnrnus MAARTENS, or EINIDHOVEN, NETHERLANDS, assre-non To name coraronarron or AMERICA, a CORPORATION or DELAWARE ELECTRIC DISCHARGE TUBE Application filed November 22, 1929, Serial No. 408,963, and in the Netherlands December 15, 1928.

This invention has reference to an electric discharge tube.

Heretofore the applicant has suggested that the gas residues or gas impurities formed during the operation of electric discharge tubes should be removed from the atmosphere of the tube by inserting zirconium in the tube and arranging it at such a point that during the operation of the tube it assumes a temperature which enables it to combine with gas residues or gas impurities.

Now the applicant has found, and it is this in which the invention consists, that the purifying action of the zirconium can be in tensified if members which do not constitute electrodes and which consist partially or completely of zirconium are shaped into such a form and arranged in the tube in such a manner that during the operation of the tube several parts of the zirconium assume different temperatures. It has been found that the temperature at which the zirconium combines with a given gas to the greatest extent is different for different gases. Owing to the fact that several parts of the zirconium assume different temperatures, the various gas residues or gas impurities will be bound or absorbed to a more satisfactory extent than if the zirconium as a whole assumes the same temperature. The zirconium may be arranged in the tube in such a manner that during the operation of the tube several parts of the zirconium assume the temperatures which are most favorable for combining with various gases.

If the tube comprises an incandescent cathode, good results may be obtained by arranging the zirconium at least partly in the vicinity of the incandescent cathode. If the tube comprises a. helically wound cathode the zirconium may be arranged with advantage partially inside and partially outside the cylinder formed by the incandescent cathode.

The invention will be more clearly understood by reference to the accompanying drawing, in which, by way of example, an embodiment thereof is illustrated. Referring to the figure, the pinch 1 of the stem 2 in the discharge tube 3 has mounted on it the various electrodes enclosed within the tube. The two anodes 4- and 5 are secured to the pinch by means of supporting Wires 6 and 7, and the incandescent cathode 8 which is preferably constructed as a VVehnelt cathode is carried by supporting wires 9 and 10. The top of the supporting wire 9 has secured to it a zirconium wire 11 which ispartially inside and partially outside the cylinder formed by the helically wound cathode.

Owing to this arrangement the zirconium P will exhibit a temperature drop and during the operation of the tube the part enclosed within the cylinder referred to will assume a higher temperature than the part outside the said cylinder. to combine with various gases as far as possible.

The discharge tube shown contains a gaseous filling which consists, for example, of one or more rare gases which may have added to them metal vapors such as mercury vapor, and the tube may be used for twophase rectification of alternating currents. It is, of course, obvious that the invention may be applied to other kinds of electric discharge tubes which are used for other purposes such as X-ray tubes, discharge tubes for use in radio-telegraphy and telephony, etc. In the latter case, a control electrode may be placed between the cathode 8 and the anodes 4 and 5.

What I claim is:

1. An electron discharge device comprising an evacuated envelope containing cooperating electrodes one of which is heatable, an inwardly extending support on the wall of said envelope, and an'elongated coherent body of zirconium secured at one end to said support with its free end sufficiently near said heatablc electrode to cause said free end to be heated to a temperature which renders said body capable of combining permanently with the deleterious gases evolved in said envelope.

2. An electron discharge device comprising an evacuated envelope containing cooperating electrodes, one of which is heatable, an inwardly extending support joined at one end to said envelope and with its free end spaced away from said heatable electrode,

This enables the zirconium and a rod of coherent zirconium with one end secured to the free end of said rod and its other end in closer proximity to said heat able electrode.

3. An electron discharge device comprising an evacuated envelope containing cooperating electrodes, one of which is heatable, a metal support secured to said envelope, and a rod of coherent zirconium secured at one end to said support to project toward said heatable electrode with its free end in proximity to said heatable electrode.

4. An electron discharge device comprising a sealed envelope, an anode, a cathode comprising a filament operable at high temperature and shaped into a helical coil, a support adjacent one end of said coil, and a rod of coherent zirconium mounted coaxially of said coil with one end secured to said support and its free end inside said coil.

JOHANNES HENDRICUS JOSEPHUS MAARTENS. 

